1. Field of the Invention
The present invention relates to a semiconductor device having a semiconductor element using a non-single crystal semiconductor layer and a manufacturing method of the semiconductor device.
2. Description of the Related Art
Currently, it is important to make various devices, such as wireless chips and sensors, into a thinner shape in miniaturizing products, and the technique and the application range spread rapidly. Such various devices which are made thin are flexible to some extent and thus the devices can be provided for an object having a curved surface.
Therefore, a technique of manufacturing a semiconductor device is proposed, in which an element layer including a thin film transistor which is formed over a glass substrate is separated from the substrate and transferred to another substrate, for example, a plastic film or the like.
The present applicant proposes techniques of separation and transfer, which are mentioned in Patent Document 1 (Japanese Published Patent Application No. H8-288522) and Patent Document 2 (Japanese Published Patent Application No. H8-250745). In Patent Document 1, a technique is described in which separation is performed by removing a silicon oxide layer, which is to be a separation layer, by wet etching. In Patent Document 2, a technique is described in which separation is performed by removing a silicon layer, which is to be a separation layer, by dry etching.
Further, the present applicant proposes techniques of separation and transfer, which is mentioned in Patent Document 3 (Japanese Published Patent Application No. 2003-174153). In Patent Document 3, a technique is described in which, in forming a metal layer (Ti, Al, Ta, W, Mo, Cu, Cr, Nd, Fe, Ni, Co, Ru, Rh, Pd, Os, or Ir) over a substrate and stacking an oxide layer thereover, a metal oxide layer of the metal layer is formed at the interface between the metal layer and an oxide layer, and the metal oxide layer is utilized for separation in a subsequent step.
In Patent Document 4 (Japanese Published Patent Application No. 2004-78991), a semiconductor device is disclosed in which, a semiconductor chip with the size of less than or equal to 0.5 mm is embedded in a paper- or film-like medium, so that tolerance for bending and concentrated loading is improved.